<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<button id="btn">点我</button>
<form action="https://www.baidu.com" method="post">
    <input type="password" name="password" id="password">
    <input type="submit" value="">
</form>
<script src="main4.js"></script>
</body>
</html>